From: Yu Kuai yukuai3@huawei.com
hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6JN1I CVE: NA
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status_resync() will calculate 'curr_resync - recovery_active' to show user a progress bar like following:
[============>........] resync = 61.4%
'curr_resync' and 'recovery_active' is updated in md_do_sync(), and status_resync() can read them concurrently, hence it's possible that 'curr_resync - recovery_active' can overflow to a huge number. In this case status_resync() will be stuck in the loop to print a large amount of '=', which will end up soft lockup.
Fix the problem by setting 'resync' to MD_RESYNC_ACTIVE in this case, this way resync in progress will be reported to user.
Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- drivers/md/md.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c index bf3a632176e8..e072ccb08735 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8076,16 +8076,16 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev) } else if (resync > max_sectors) { resync = max_sectors; } else { - resync -= atomic_read(&mddev->recovery_active); - if (resync < MD_RESYNC_ACTIVE) { - /* - * Resync has started, but the subtraction has - * yielded one of the special values. Force it - * to active to ensure the status reports an - * active resync. - */ + res = atomic_read(&mddev->recovery_active); + /* + * Resync has started, but the subtraction has overflowed or + * yielded one of the special values. Force it to active to + * ensure the status reports an active resync. + */ + if (resync < res || resync - res < MD_RESYNC_ACTIVE) resync = MD_RESYNC_ACTIVE; - } + else + resync -= res; }
if (resync == MD_RESYNC_NONE) {